 
Main Menu
|
|
Nevada Classics
|
|
Advertise at CC
|
|
November 2024
|
| S |
M |
T |
W |
T |
F |
S |
| |
|
|
|
|
1 |
2 |
| 3 |
4 |
5 |
6 |
7 |
8 |
9 |
| 10 |
11 |
12 |
13 |
14 |
15 |
16 |
| 17 |
18 |
19 |
20 |
21 |
22 |
23 |
| 24 |
25 |
26 |
27 |
28 |
29 |
30 |
|
|
CC Advertisers
|
|
06-01-2006, 10:06 AM
|
|
CC Member
|
|
|
Join Date: Jan 2003
Location: Marietta,
ga
Cobra Make, Engine: Unique 427 S/C 427 done by Southern Automotive
Posts: 15
|
|
Not Ranked
3:31 vs 3:54
I'm running a 427 in my Unique replica with a 3:54, what's the upside or downside of going to a 3:31 other than lower high end rev ?
Lou
|
-
Advertising
06-01-2006, 12:12 PM
|
 |
CC Member
|
|
|
Join Date: Dec 2001
Location: San Diego,
CA
Cobra Make, Engine:
Posts: 2,979
|
|
Not Ranked
What trans are you running. Having the 3.31 will make first gear more usable.
__________________
Remember, It's never too early to start beefing up your obituary.
|
06-01-2006, 12:14 PM
|
 |
Beam Me Up Scottie
|
|
|
Join Date: Aug 2004
Location: Squantum (part of Quincy),
MA
Cobra Make, Engine: SPF1049 Titanium w/black stripes, 351W with Trick Flow Heads, Tremec 3550
Posts: 7,592
|
|
Not Ranked
3:54 to 3:31 rear gears
Upside
Higher top speed
Better gas mileage
Downside
Slower acceleration
$$$$$
Time to do the swap
__________________
Warren
'Liberals are maggots upon the life of this planet and need to get off at the next rotation.' (Jamo 2008)
|
06-01-2006, 12:16 PM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: Aug 2005
Location: Toronto, Canada,
Ont
Cobra Make, Engine: Shelby CSX 4995, Keith Craft built 427 SO
Posts: 1,168
|
|
Not Ranked
 Does one really need a top end greater than 160 mph? I prefer the neck snapping hole shots with the 3.54. IMHO
__________________
"The 427 Cobra is easily the highest performance car ever sold for street use. A decent 427 - not the worst, not the best, will go from zero to 100 mph and back down again to zero in less than 14 seconds. All thing considered, you can put together a pretty good argument that the 427 Cobra is the ultimate performance car, judged on any basis you want to name." Taken from; Corvette, The Sensuous American 
|
06-01-2006, 01:10 PM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: Mar 2002
Location: God's country,
ME
Cobra Make, Engine: Original ERA 427sc, Powered by Gessford
Posts: 2,678
|
|
Not Ranked
What cam? Figure out your final drive rpm with each rear ratio and pick which ever best matches the power band of your cam based on the type of driving you do.
__________________
Replica is not a dirty word.
"If you can't be a good example, then you'll just have to be a horrible warning."
|
06-01-2006, 03:02 PM
|
|
CC Member
|
|
|
Join Date: May 2001
Location: niceville fl,
fl
Cobra Make, Engine: Hunter #28; 396 Cleveland stroker; more than 495 HP; TKO 5 speed
Posts: 442
|
|
Not Ranked
If you spend much time spinning your tires is 2nd.
you will probably go faster, spinning tires is slow and dangereous.
I find a 3.08 about perfect for street. With race slicks I would be better off with a 3.55 because only then can the excessive torque be utilized
gn
|
06-01-2006, 05:59 PM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: Mar 2001
Location: Southern Connecticut,
CT
Cobra Make, Engine: SPF - 351W, 944 non-turbo
Posts: 2,105
|
|
Not Ranked
4Speed, 5speed, OD? I'm running a 3.73 with a Tremec 5 speed. 0.68 OD. It works out to 2.6 overall or so in top gear. If I had it to do all over again I would get a taller gear in the back. Maybe 3.25 or so.
Bob
|
06-03-2006, 10:43 PM
|
|
CC Member
|
|
|
Join Date: Jan 2003
Location: Marietta,
ga
Cobra Make, Engine: Unique 427 S/C 427 done by Southern Automotive
Posts: 15
|
|
Not Ranked
Not very swift to leave out the tranny I'm running in the 427......
4speed toploader, had the option for a Tremec 5 speed but I wanted to be like Carroll.....
Lou
|
06-04-2006, 01:49 AM
|
 |
Junior Member
|
|
|
Join Date: May 2001
Location: El Dorado Hills, CA,
CA
Cobra Make, Engine: Hurricane Cobra HM 1007, 390FE
Posts: 62
|
|
Not Ranked
I have 325 Gears in the rear. At a 1 to 1 ratio in high gear. 3200 rpms = 80 mph. I had 331 rear gears in my last Cobra and got tierd of people passing me on the freeway. At 80 I was running around 4000 rpms.
__________________
Hurricane Cobra HM 1007
|
06-04-2006, 05:23 AM
|
|
CC Member
|
|
|
Join Date: Apr 1999
Location: cleveland,
OH
Cobra Make, Engine: CSX4000, 427
Posts: 1,999
|
|
Not Ranked
Quote:
|
Originally Posted by for27
I'm running a 427 in my Unique replica with a 3:54, what's the upside or downside of going to a 3:31 other than lower high end rev ?
Lou
|
My guess is that they are so close, you probably won't notice that much difference, and if you didn't know that the gears were switched, you may not even know there was a switch when driving it.
__________________
"After jumping into an early lead, Miles pitted for no reason. He let the entire field go by before re-entering the race. The crowd was jumping up and down as he stunned the Chevrolet drivers by easily passing the entire field to finish second behind MacDonald's other team Cobra. The Corvette people were completely demoralized."
|
06-04-2006, 07:04 AM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: May 2001
Location: Florence,
AL
Cobra Make, Engine: RCR GT 40 & 1966 Fairlane 390 5 speed
Posts: 4,511
|
|
Not Ranked
car math
Here is a link that will allow you to figure the differents in gears, tires and trannies. Tires size plays a big part in the overall ratio. You have to decide what you want to do, fast out of the hole, low rpms on the freeway. Or a compromise. Quick away from the red light is good  I chose a 5 speed to give me a little of both worlds.
http://www.secondstrike.com/Technical/GearCalc.asp
Dwight
__________________
''Life's tough.....it's even tougher if you're stupid.'' ~ John Wayne
"Happiness Is A Belt-Fed Weapon"
life's goal should be; "to be smarter than inanimate objects"
|
06-04-2006, 11:41 AM
|
 |
CC Member
|
|
|
Join Date: Nov 2000
Location: Tucson,
Az
Cobra Make, Engine: Superformance 427 Side-Oiler
Posts: 2,156
|
|
Not Ranked
For27-which toploader?WR or CR.Makes a big difference.
__________________
The rest of the world can have their opinion about the United States just as soon as WE give it to them.
|
06-04-2006, 05:04 PM
|
|
CC Member
|
|
|
Join Date: May 2004
Posts: 173
|
|
Not Ranked
With a 4 spd top loader, I had 331 then went to 354 , I think I might try 331 one more time . longer first , unreal 2nd !!! little more normal in 4th . The 354 change I did with the 390FE , later I went with a 427 , so I would like to retry the 331 .
|
06-04-2006, 08:08 PM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: Jan 2001
Location: Santa Barbara, Ca.,
ca
Cobra Make, Engine: R.U.C.C. with a 427FE, toploader
Posts: 1,435
|
|
Not Ranked
I have 354 and a Toploader, I'm now looking for a 5 speed 
__________________
Mike Z
Nothing sucks more than that moment during an argument when you realize you’re wrong.
|
06-04-2006, 08:30 PM
|
|
Senior Club Cobra Member
|
|
|
Join Date: Jul 2002
Cobra Make, Engine:
Posts: 15,712
|
|
Not Ranked
3:31, I'm cruising along about 60 mph on the freeway, and just for kicks, drop it into 2nd and nail it! Eh eh, love doing that 2nd gear thing at freeway speeds, takes off like a rocket! 
Close ratio top loader, the gear ratios in the trans DO make a difference as to what you can and can't do as well as the rear end ratio.
Oh by the way, I got 11.5 mpg with my 427 and DUAL carbs on the last tank of gas. Steady cruising at about 2800 rpm, not bad! Heck my Jeep V8 does only slightly better!
Last edited by Excaliber; 06-04-2006 at 08:33 PM..
|
06-04-2006, 08:39 PM
|
 |
Senior Club Cobra Member
|
|
|
Join Date: Nov 1999
Location: Folsom,
CA
Cobra Make, Engine: ERA 623, 427 S/C Cobra. Ford FE 428 Cobra Jet, Ford Nascar TL 4speed - with a touch of raw; "less is more" theme
Posts: 3,882
|
|
Not Ranked
With the torque in a stong FE, you'll do better overall with the 3.31 rear gearset - it just pulls through first gear and its nice to have a little extra in 4th gear. Most people I know that had 3.54s/FE combo are much happier with 3.31s now. My former car had the 3.08 differential and an FE, and overall I feel the 3.31s are about right, and particularly with the wide-ratio trans Toploader or custom big-Toploader with wide ratio setup. Other friends with SPFs running the rear 3.73 gears have changed to 3.27s and like that much better, but for those running the .68 overdrive they say its a tad too tall if you are running a larger cam.
I'm considering (waffling about) a 5-speed road race trans myself but sure do like the way the Toploader / 3.31 setup runs with a larger camshaft for everything except long highway trips. That .82 5th gear would be nice; which drops from 3,000 rpm higway cruising to 2,450rpms. As others have noted, you need to provide your cam/motors specs too to get a better idea from us.
__________________
Duane
Western States Cobra Group 1998-2016.
|
06-05-2006, 06:05 PM
|
|
CC Member
|
|
|
Join Date: May 2004
Posts: 173
|
|
Not Ranked
With my 400 HP 390 , 4 spd top loader , 331 gears , I got 18 mpg on trips . Now 10 with new set up .
|
06-07-2006, 02:09 PM
|
|
CC Member
|
|
|
Join Date: Jan 2003
Location: Marietta,
ga
Cobra Make, Engine: Unique 427 S/C 427 done by Southern Automotive
Posts: 15
|
|
Not Ranked
3:31 vs 3:54
Thanks to all for the great feedback and info. Hey Dwight, that link you passed along was great for sorting out all the possibilities. I decided that the 3:31 with my wide ratio toploader is the way to go. A also received a suggestion to change the pair of 295/50's on the rear to 275/60's to achieve the same results. For sure a cheaper way to go, but I don't think I would have liked the stance of the car and also don't know if the car would have felt as planted as it does now.
Thanks again to all,
Lou
|
06-07-2006, 02:17 PM
|
 |
CC Member
|
|
|
Join Date: Aug 2003
Location: Southeast,
CT
Cobra Make, Engine: ERA #375 427 S/C - 428FE - Toploader - 1968 AMX 390 Go Pack 4 Speed - My Daily Driver is a 2004 Crossfire
Posts: 872
|
|
Not Ranked
I have a 3.31 rear with 4 speed Toploader. The only downside to this combo is trying to drive the car slow in a parking lot. The car will tend to lurch, lurch, lurch at 5 MPH or less. Other than that, it is really a fine gear setup with the toploader. In first I can get up to about 60MPH. You may not be out of 2nd at all in city traffic. The car will pull well in just about any gear.
You can take off from a dead stop in 2nd.
I would never think about changing this combo... unless you wanted to drag race... otherwise, you will be happy with it.
__________________
Art in CT
See My Website at http://www.lithicsnet.com
A car can massage organs which no masseur can reach. It is the one remedy for the disorders of the great sympathetic nervous system. Jean Cocteau 1889-1963, French Author, Filmmaker
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -7. The time now is 04:21 PM.
|
Linear Mode
